PKM and cancer: Because of the importance of PK-M2 as a potential cancer drug target, and in order to systematically search for new splicing elements that mediate the PK-M2 dominant splicing patterns, we conducted an antisense oligonucleotide (ASO) screen targeting endogenous PK-M exon 10 to discover ASOs that switch the expression of the PK-M2 isoform to the PK-M1 isoform in cancer cells.